These studies are a continuation of protocol #20-1, except for the addition of probucol as one of the drugs. Since we can now normalize LDL cholesterol in patients with heterozygous familial hypercholesterolemia using a combined drug regimen, we are testing the regimen's ability to shrink atherosclerotic plaques as measured by computerized angiography. Patients are studied in the effect of treatment on levels of plasma free fatty acid.